The present invention relates to an optical disc apparatus, and more particularly to an optical disc apparatus which can read out PCM data.
In an optical disc apparatus which reproduces video data and/or audio data from a DVD (Digital Versatile Disc) and further records video data and/or audio data onto a DVD, usually, transmission and reception of data are controlled by an ATAPI controller or a SCSI controller. Many of such optical disc apparatuses can perform reproduction of PCM data recorded on a CD (Compact Disc) in addition to reproduction of data from a DVD.
FIG. 1 shows a first example of a conventional optical disc apparatus. In the optical disc apparatus, when data is to be reproduced from a DVD, reading of data is controlled by an ATAPI controller 4, data of a predetermined number of bits is read out each time by an AV decoder 11, and the data is then processed by a vide encoder 13 to be output from the apparatus. Data which is input trough an antenna or from an external apparatus is compressed into the MPEG2 format by an AV encoder 25, and then recorded onto an optical disc while recording is controlled by the ATAPI controller 4. When data is to be reproduced from a CD, PCM data is transmitted to a switching section SW through a dedicated line 31 which is connected to a front-end section 3, and a sub Q code (time information) is transmitted to the switching section SW via the ATAPI controller 4 and the AV decoder 11. As a result of switching of signal paths by the switching section SW, the PCM data and the sub Q code (time information) are supplied in synchronization to a DIT 15. In the DIT 15, digital audio data is produced from the PCM data and the time information, and then output through an S/P DIF terminal.
FIG. 2 shows a second example of a conventional optical disc apparatus. The second example is configured in the same manner as the first example except that, in place of the dedicated line 31 which is connected to the front-end section 3 in the first example, a dedicated line 41 is connected to the ATAPI controller 4. When data is to be reproduced from a CD, PCM data is read into the ATAPI controller 4, and then transmitted to the switching section SW through the dedicated line 41, and a sub Q code (time information) is transmitted to the switching section SW via the ATAPI controller 4 and the AV decoder 11. As a result of switching of signal paths by the switching section SW, the PCM data and the sub Q code (time information) are supplied in synchronization to the DIT 15.
In the first and second examples, PCM data which is transmitted through the dedicated line 31 or 41 is synchronized with time information which is transmitted through another path, by switching of the signal paths by the switching section SW. Therefore, it is difficult to control synchronization of the PCM data and the time information, and the synchronization cannot be sometimes sufficiently attained.
An apparatus for reproducing in synchronization video data and audio data is disclosed in the Unexamined Japanese Patent Application Publication No. 2000-324163. In the disclosed apparatus, time information which is added in recompression of video data is added also to a packet containing audio data which is to be reproduced at the same timing, whereby the video data and the audio data are synchronized with each other. However, the above-mentioned publication discloses only a configuration for synchronizing video and audio data in the MPEG2 format which are recorded on a DVD, and teaches nothing about a configuration for, in an optical disc apparatus which can reproduce data from a DVD, synchronizing PCM data recorded on a CD with time information.